Valley-Polarized Plasmonic Edge Mode Visualized in the Near-Infrared Spectral Range
Valley-Polarized Plasmonic Edge Mode Visualized in the Near-Infrared Spectral Range
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DOI：
10.1021/acs.nanolett.1c01841
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发表时间：
2021-07-27
期刊：
影响因子：
10.8
通讯作者：
Sannomiya, Takumi
中科院分区：
文献类型：
--
作者：
Saito, Hikaru;Yoshimoto, Daichi;Sannomiya, Takumi
谷偏振最近已被采用在光学，提供强大的波导和角动量分选。谷系统在光子晶体中的成功表明了一种等离子体对应物，它可以将拓扑光子学和拓扑凝聚态系统融合在一起，例如，具有增强的光-物质相互作用的二维材料。然而，由于金属内部的欧姆损耗，迄今为止还没有实现在近红外（NIR）或可见光谱范围内具有足够传播距离的谷等离子体激元波导。在这里，我们采用间隙表面等离子体的高折射率对比和实现宽带隙谷等离子体晶体，允许在近红外可见光范围内的波导。通过扫描透射电子显微镜阴极发光技术观察电场分布，实验证实了在1.31-1.36 eV范围内传播距离为5.3 μ m的边缘模式，这为介观有源器件中光子和载流子之间的角动量传递提供了一个实用的平台。
Valley polarization has recently been adopted in optics, offering robust waveguiding and angular momentum sorting. The success of valley systems in photonic crystals suggests a plasmonic counterpart that can merge topological photonics and topological condensed matter systems, for instance, two-dimensional materials with the enhanced light-matter interaction. However, a valley plasmonic waveguide with a sufficient propagation distance in the near-infrared (NIR) or visible spectral range has so far not been realized due to ohmic loss inside the metal. Here, we employ gap surface plasmons for high index contrasting and realize a wide-bandgap valley plasmonic crystal, allowing waveguiding in the NIR-visible range. The edge mode with a propagation distance of 5.3 mu m in the range of 1.31-1.36 eV is experimentally confirmed by visualizing the field distributions with a scanning transmission electron microscope cathodoluminescence technique, suggesting a practical platform for transferring angular momentum between photons and carriers in mesoscopic active devices.